Sensitivity of Larval Fish Transport to Location, Timing, and Behavior Using a Particle Tracking Model in Suisun Marsh, California

Abstract

We used a coupled hydrodynamic-particle tracking model to assess the rela- tive importance of factors affecting transport and entrainment risk for generalized fish larvae in Suisun Marsh in the San Francisco Estuary, California. Factors examined in- cluded location of particle release, time of particle release, vertical migration behavior, and combinations thereof. Model sensitivity was evaluated by observing particle en- trainment into a water diversion in Suisun Marsh under various scenarios and com- pared to randomized input cases. Scenarios combining two or more factors indicated nonlinear interactions, including evidence of tidal pumping on neap tides near our test diversion. Our study suggests that accurate modeling of larval transport depends on accurate determination of fish locations, tidal and residual time scale circulation simula- tion, and fish behavior during early life stages. We also examined appropriate ap- proaches to modeling these factors.